Sheet metal shaper



SHEET METAL SHAPER Filed Dec. ll, 19:59A

43 l, I* 44 f A 22 YadIO/wm/ Patente-d Oc't. 28, 1941 SHEET METAL sHAPER Albert S. Johann, Milwaukee, Wis., assignor to n Milwaukee Electric Tool Corporation, Milwaukee, Wis., a corporation of Wisconsin Application December 11, 1939, serial No. 308,621

2 Claims. (01.153-48) The present invention relates generally to vimprovements in the art of shaping sheet metal and relates more particularly to improvements in the construction and operation of portable tools especially adapted to .restore or re-shape ldamaged 4sheet metal automobile parts such as bodies,

'fenders and the like.

An object of the invention is to provide an improved sheetvmetal Shaper or former, which is simple and compact in construction, and which `is moreover highly ellcient and iiexible in use.

Many diierent typesof tools and appliances have heretofore been utilized in the automobile repair .industry to restore damaged sheet metal partssuch as bodies and fenders, to normal condition. It is customary in repairing dented sheet metal parts,vto bump out the dents or kinks to the approximate origina] position of the metal, rand to subsequently iron out theerough spots with a portable pneumatically .operated repair tool or .assemblage having a yoke of desirable zshape, one end of which carries an anvil block, 'and to the other end of which is secured a pneumatic hammer cooperating with a dolly or plunger coacting with the anvil through the distorted area of the sheet metal which is being straightrened. While the yokes of these prior pneumatic about so as to cause the dolly and anvil to travel along the distorted areas, they cannot be freely tilted and rotated about the axes of the impact rand reaction element of the hammer assemblage,

thus making it diflicult and sometimes impossible to advance the tool lin every `desiredv direction and at variable angles so as to form smooth curves. The prior assemblages are also rather di'cult to position with reference to some classes of work and in relatively inaccessible places, and therefore do not meet many requirements and cannot be readily manipulatedk `to quickly produce a lmade possible and manipulation of the assemblage v is greatly facilitated.

Another specic object of the invention is to provide various improvements in the construction of portable hammer units, whereby such tools may be readily randrluickly applied to the work' `sheet metal straightening vtools can be moved and manipulated in relatively inaccessible places.

A further specific object of my invention is to provide ar compact iandndurable portable sheet metal straightening tool which is conveniently manipulable to most eii'ectively perform different classes of work, and which is especially adapted to produce smooth curvature of sheet metal kin any desired direction. f

Still another. specific .object ofvthis invention is to `provide a new and useful pneumatic hammer assemblage wherein the hammer cylinder rmay .be quickly and positively withdrawn Afrom or advanced toward Athe work, and in which .excessive play is eliminated between movable parts o-f the assemblage. v

An `additional*specific object of the invention v is 4toprovide 4improved means for retaining the Iportion of the sheet metal which is being operated upc-n by .apneumatic hammer or the like in contact with the anvil, and for preventing eX- ysheet metal shaper built in accordance with the invention, may .be had by .referring to the drawing accompanying and forming a part .of this speciiilcation wherein like reference vcharacters desiglnate the same o-r similar parts in the various views. Y

Fig. 1 is a side elevation-of one of the improved 'portable sheet metal shapers, showing the hammer actuated dolly brought into Contact Awith ythe anvil; y

y Vliig. 2 is an enlarged central longitudinal section throughthe pneumatic hammer and thevanvil, showing the dolly in contact with .the an- Fig. 3 lis a transverse section through the assemblage of Fig. 2, taken falong the-line 3 3.

LWhile I havey shown 'and described one ycom- '.mercial embodiment of `my improved portable shaper,-it is not the intent to unnecessarily restrict the scopev or nutility of the invention, and

:it is to 4be understood that the hammer and anvil supporting frame maybe of diverse shapes depending vupon the specic use of the tool.

1 Referring to the drawing, the improved portable sheet meta-l shaper shown therein comprises *in general, va tubular yC-shaped frame At having zontal frame end 8 by means of a clamping bolt I1, and having a bore I8 within which the hammer cylinder I4 is snugly but slidably confined; and an adjusting pinion I9 rotatably mounted within the fitting I6 and coacting with rack teeth 28 on the cylinder I4, to positively move the hammer assemblage and the associated parts toward or away from the anvil block 9.

The frame is preferably formed of a relatively rigid but light steel tube, and the pivot element I may be either permanently or detachably secured to the vertically directed framek end 1 in any desired manner. The element I0 has a head 2I at its upper end provided with a spherical zone surface with which the anvil block 9 coacts as shown in Fig. 2; and the block 9 is rectangular in shape and is provided with a centrally flat and marginally convexly curved surface 22' which is preferably curved in all directions away from the fiat area and is rounded at its edges as kshown in Figs. 1 and 2. The anvil block 9 is freely rotatable and slightly tiltable in all directions, upon the spherical zone surface 2I of its supporting element I0, and may be replaced for performing different Work by other anvils of different .shapes and sizes. The dolly block I I which is cooperable with the anvil block I0 through the work, has a conical central recess with which a lower spherical zcne surface 23 on the head I2 of the suspension pin I3 coacts so as to permit bothfree rotation and limited tilting of the block II in all directions, in unison with the reaction block 9; and the dolly or block II is permanently suspended from the pin head rI2 by means of a retaining collar 24, see Fig. 2. `The dolly block I I is circular in shape and is also provided with a centrally flat and marginally concavely curved surface 25 corresponding in shape to that of the anvil surface 22, and this surface 25 is surrounded by an annular depending lip 26 spaced from and surrounding the surfaces 2'2, 25 and adapted to contact the upper surface of the intervening work sheet. As shown in Figs. 1 and 2, the annular lip 26 is rounded and extends downwardly beyond the plane of the lower edge of the surface 25, but not below the plane of the curved lower edges of the surface 22, so that the lip 26 will always properly engage the work and will position the ironing surfaces 22, 25 so as to most effectively cooperate with the area of the work kbeing operated upon.

The pneumatic hammer comprising the cylinder I4 and the plunger I5, is disposed in axial alinement with the impact pin I3; and the cylinder I4 is provided with a central bore 21 in which the plunger I is reciprocable. The lower end of the bore 21 is normally closed by a removable bushing 28 in which the impact pin I3 is snugly but slidably confined, and the pin I3 has an annular groove 29 with which a latch pin 3|] coacts to normally retain the pin I3 within the bushing 2'8. The groove 29 should be of sufficient width to permit the impact pin I3 to move axially `relative to the bushing 28 and cylinder I4, and the latch pin 39 should not interfere with this movement and is held in place by a light spring 3I so as to permit the pin I3 and dolly block II to be readily withdrawn endwise from the bushing 28. The portion of the dolly suspension pin I3 between the bushing 28 and the pin head I2, is embraced by a collar 32, the lower end of which engages the head I2, and the upper end of which has an integral stop flange adapted to engage the lower end of the bushing 28; and the upper extremity of the pin I3 projects slightly above the upper end of the bushing 28 and into the cylinder bore 21.

The hammer plunger I5 fits snugly within the main cylinder bore 21, and has a reduced integral upper end extension 33 which is reciprocable within a reduced bore 34 in the cylinder I4 to provide a cushioning chamber 35 above the impact piston. A central passage 36 within the plunger I5, leads from the lower plunger displacement chamber 31 to a point above the upper displacement chamber 38;'and is communicable through a lateral port 39, with a compressed air supply duct 40 formed in the cylinder I4 and communicating with a flexible air supplypipe 4I. The upper reduced portion of the plunger I5 is also provided with an annular groove 4I which establishes communication between the duct 40 and the chamber 38 when the plunger l5 is lifted. The lower and upper displacement chambers 31, 38 are respectively communicable through ports 42, 43 with a groove 44 formed in the cylinder I4 and communicating with the ambient atmosphere, and when the various parts of the hammer are in the position shown in Fig. 2, the passage 36v is sealed by the pin I3 and the hammer I5 must be lifted before air can be admitted to either of the plunger displacement chambers 31, 38. The air supply pipe 4I should also be provided with a cut-off valve so that the air can be shut off when the tool is not in use.

As previously indicated, the hammer cylinder -KI4 and the parts carried thereby, are slidable in the vertical bore I8 of the fitting I6, by means of the pinion I8 coacting with the rack teeth 20 formed on the cylinder I4. The pinion I9 is secured to a shaft 45 by a key 45', and the shaft 45 is journalled in the fitting I6 and in a removable plug 46 coacting with the fitting to normally confine the pinion I9. The shaft 45 has a central bore 41 extending inwardly from one end, and also has an actuating crank or handle 48 secured to its opposite end; and the end of the pinion I9 facing Ythe plug 46 is provided with an annular series of radial ratchet teeth 49 adapted to coact with a similar series of teeth formed on the adjacent side of an annular member 56 which is slidable along the shaft 45 between the pinion I8 and plug 46. The member 50 while being movable toward and away from the pinion I9, is locked against rotation with the shaft 45 by means of spline projections 5I formed integral with .the plug 46 and engaging diametrically opposite slots 5I formed in the member 50. The two sets of teeth are constantly urged toward interlocking position as shown in Fig. 3, by means of a compression spring 52' interposed between the plug 46 and the member 50; and the member 50 is adapted to be forced to the right and out of engagement with the pinion I9 as viewed in Fig. 3, by means of a plunger 53 located Within the shaft bore 41 and having a button 54-at one end, and prongs 55 at its opposite end projecting through slots 56 in the medial portion of the shaft 45,. With this assemblageof elements, the pinion I9 is constantly drivingly connected .to the shaft 45 by the key 45'.and .the member 50 is constantly locked against rotation by the plug projections I, but. rotationv of the shaft by the handle 48m-lll cause the pinion teeth. 49. to ratchet' over vthe xedteeth of the memberi50 andto Arotate the pinion I9, thereby. moving. the hammercylinder I4 downwardly.` The hammer cylinder I4 will be locked in any position of adjustment and against lifting by theratchet teeth, but when vpressureis applied tothe button 54, this locking connection is interrupted and the cylinder I4 may be .moved freelywithin the fitting bore I8 either toward or away from the anvil block 9.A The fitting I6 is normally rigidly clamped to the'horizontalframe end 8 by means of the bolt I 1, and a pin 51 coacts with a notch in the end of the fitting as shown in Fig. l, in order to properly position .the'center line of the cylinder I4 in line with the axis of the vertical frame end 1.'. The pinion I9 is also preferably provided with spiral teeth which mesh with the inclined teeth 28 on the cylinder I4, and this feature is extremely important since it eliminates play or lost motion between the tting I6, pinion I9 and cylinder I4 at all times.

During normal operation and use of the improved sheet metal straightener, the dolly block I I may be withdrawn from the anvil block 9 sufficient to permit these parts to be positioned on opposite sides of the sheet metal work which is to be ironed out or straightened, by utilizing the button 54 and plunger 53 to release the pinion I9 from the member 50, and by subsequently sliding the cylinder I4 manually along the tting bore I8. When the blocks 9, II have been thus positioned below and above the work, these blocks may be brought into operative position with the work, by rotating the pinion I9 with the aid of the handle 48, and the dolly rim or lip 26 may be brought into substantial engagement with the top of thev sheet metal about the area which is to be straightened. 'I'he ratchet teeth 49 Will lock the blocks 9, II against subsequent spreading until the release button 54 is pressed. When this adjustment has been properly made, the blocks 9, II. should be freely slidable along the sheet metal work, and the latter should not be too firmly clamped between the blocks.

As the compressed air is admitted to the passage 36 through the duct 40 and port 39, this air acting upon the upper unbalanced area of the plunger I5 at the top of the passage 36 and upon the upper end of the pin I3, will quickly raise the plunger to admit air to the chamber 41, and this compressed air acting upon the lower face of the plunger I5 will interrupt communication between the port 39 and duct 46 and will establish communication between the duct 40 and the upper chamber 38 through the annular groove 4I' of the plunger. The air from within the passage 36 and chamber 31 will then escape through the lower exhaust port 42 to atmosphere, and the compressed air which enters the displacement chamber 38 past the groove 4 I will quickly force the plunger I5 downwardly to again cut-off communication between the supply duct 40 and chamber 38 through the groove 4I.` The air from within the chamber 38 quickly escapes through the upper exhaust port 43 when the supply is cut-off, thus again permitting the cornpressed air entering the passage 36 and chamber 31 to elevate the plunger I5. As this cycle of operations is rapidly and automatically repeated, a rapid succession of impulses is delivered to the impact pin I3 and from 'thence to the dolly block I.I,.and .the air confined in the upper cushioning chamber 35 augments thesedownward impacts ,but lcushions the returnstroke of the plunger. I5.

Because of the fact that both of the :work engaging blocks 9, II are freely rotatable and Auni-l versally tiltable relative to the C-frame 6, this frame may be utilized to slide the ironing blocks 9, II y,along the curved areas of the work, and maybe rotated or tilted in any desired'direction Without interfering with the force and desirable direction of application of the impacts. During tilting of the frame 6, the annular lip 26 of the dolly block II maintainsboth of the blocks 9, 'II in proper relation to each other and tothe surfaces'of the Work which are being straightened, and the blocks 9, II may be advanced along plane, simple curved, or compound curved vareas withl equal facility. When a job has been completed, either the handle 48 and pinion may be.` utilized to withdraw the dolly block II away from the anvil block 9, or the push button 54 may be used to disengage the pinion driving con` nection and to permit more rapid manual Withdrawal of the hammer cylinder I4 and block I I, and the tool may then be freely removed from the work.

From the foregoing detailed description it will be apparent that my present invention provides an improved sheet metal straightening tool which imay be effectively utilized to iron out slight bumps or kinks in sheet metal and to form either a plane or smoothly curved surface at the distorted portions of the Work. While I have shown and described a particular type of pneumatic hammer, many other types of these hammers may be utilized, but the mounting of the anvil and dolly block so that these blocks may rotate and tilt universally, is extremely important since thisl mounting makes it possible to produce smooth ironing of the metal under practically all conditions of operation. By permitting rotation of the manipulating frame 6 relative to the ironing blocks, the frame may be swung in any direction to clear obstructions, and the tilting of the blocks relative to the central axis of the hammer likewise permits swinging of the manipulating frame 6 in any direction while advancing the blocks along the surface being straightened. The lip 26 which coacts with the outer surface of the work acts as a pressure head and is extremely effective in maintaining proper coaction between the inner and outer straightening blocks, and the use of inclined teeth 20 cooperating with a spiral toothed pinion I9 eliminates excessive play or lost motion and retains the blocks 9, II in proper position with respect to the surfaces of the work. The lock afforded by the teeth 49 of the pinion coacting with the teeth of the non-rotatable member 50, permits convenient downward adjustment of the cylinder I4 but positively prevents the blocks 9, II from separating, unless the release button 54 is pressed, thus preventing the blocks from moving vto limit this invention to the exact details of construction or to the precise mode of use, here in shown and described for various modications within the scope of the claims may occur to persons skilled in the art.

I claim:

1. In combination, a portable C-shaped frame having upper and lower ends, an anvil universally tiltable upon said lower frame end, a hammer cylinder adjustable with respect to said upper frame end toward said anvil, an impact pin protruding from the lower end of said cylinder, a piston reciprocable within said cylinder to deliver blows tosaid pin, and a dolly block interposed between said pin and said anvil, said block being universally tiltable relative to said cylinder and pin and having an annular groove facing said anvil and providing a peripheral work engaging lip spaced from and surrounding the iajxisy of said pin for effecting simultaneous tilting of the anvil and dolly block.

2. In combination, a portable C-shaped frame having upper and lower ends, an anvil universally tiltable upon said lower frame end, a hammer cylinder adjustable with respect to said upper frame end toward said anvil, an impact pin protruding from the lower end of said cylinder, a piston reciprocable within said cylinder to deliver blows to said pin, and a dolly block interposed between said pin and said anvil, said block being-universally tiltable relative to said cylinder and pin and having an annular groove facing said anvil and providing a peripheral work engaging lip spaced from and surrounding the axis of said pin for effecting simultaneous tilting of the anvil and dolly block, and said pin being movable along its axis and relative to said dolly block and anvil.

ALBERT S. JOHANN. 

